1. Field of the Invention
The present invention relates to slide fastening devices for joining together fabric and similar material. More particularly, the present invention is directed to a slide fastening device for providing a water-resistant seal.
2. Description of Related Art
In recent years there has been significant improvements in the development of water resistant fabrics for a wide variety of applications, such as outdoor clothing, sports equipment, etc. In addition to improved nylon materials with coatings of polyurethane, polyethylene, or similar polymer, a number of more comfortable "breathable" waterproof fabrics have been developed which repel water while permitting the dissipation of water vapor (e.g. perspiration). Methods for creating such a material from polytetrafluoroethylene (PTFE) is disclosed in a number of patents, including U.S. Pat. No. 3,953,566 issued Apr. 27, 1976, to Gore.
With the improvements in imparting waterproofness to fabrics, the seams connecting the fabric material have become the primary location where water penetration tends to occur. This problem is probably most severe at seams connected with resealable closures, such as access zippers, zippered pockets, and underarm "pit-zips" and other openings provided for adjustable ventilation. While these resealable seams are necessary for the proper functioning of the product, they have proven to be particularly difficult to seal properly.
In certain extreme environments, such as on over-water flight suits or life preservers, watertight zippers have been employed for many years. Generally these closures must be made completely waterproof for protection in life threatening situations where a garment or container must be thoroughly watertight and the zippers usually rely on extra barrier layer or layers to seal against any possible water penetration. Among the problems with this approach is that the zippers are very difficult to operate (i.e. usually requiring two hands to open and close), they tend to be far too stiff and unyielding to normal flex-detracting from the "hand" (i.e. the normal texture, drape, bend and feel) of the fabric, and they employ mechanisms which are considered overly complicated and expensive to manufacture for everyday use. Examples of such devices are found in United Kingdom Patent 607,586 issued May 5, 1944, to B.F. Goodrich Company, U.S. Pat. No. 2,532,724 issued Dec. 5, 1950, to Krupp, and European Patent Application 87-103404.7 filed Mar. 10, 1987, by Yoshida Kogyo K.K.
For less demanding environments, a number of attempts have been made to develop a slide fastener which is water resistant yet is somewhat easier to operate. Unfortunately, most of these devices again employ some form of barrier layer to help resist water penetration. In U.S. Pat. No. 4,601,085 issued Jul. 22, 1986, to Yoshida et al. a slide fastener is proposed with a stringer tape (i.e. the material used to attach the zipper elements to the fabric) being made water resistant through one of a variety of methods, including by attaching multiple layers of water sealant material or constructing the entire tape from water proof material. In order to improve water tightness, the patent employs dual rows of offset slide fastener elements (e.g. zipper teeth) with a barrier layer of stringer tape mounted across the opening between them. For further improved water-resistance, the patent suggests using a "double-coupling" construction which actually overlaps the stringer tapes between the slide fastener elements.
Although the approach suggested in the Yoshida et al. patent may help reduce wicking of water through the stringer tape material, it is also deficient in a number of respects. First, those mechanisms taught for imparting waterproofness to the stringer tapes by imposing an intermediate barrier layer within the stringer tapes are considered to be too difficult and costly to be readily implemented. Second, the patent offers only partial solutions of how to avoid the seepage of water through stitched seams holding the slide fastener elements in place. Third, the patent is silent as to how to mount the zipper to avoid leakage through the seams anchoring the stringer tapes to the fabric. Finally, the use of an intermediate barrier layer, and especially the suggested double-coupling construction, would also appear to hinder unrestricted operation of the zipper.
Some of these deficiencies are addressed in U.S. Pat. No. 4,888,859 issued Dec. 26, 1989, to Horita. In this patent a single row of zipper elements is anchored to a stringer tape and then the stringer tape is coated on one side by a waterproof layer. In order to resist water seepage through the slide fastener elements, the teeth are mounted so as to create a barrier layer with the stringer tapes abutting one another in a closed position (necessarily requiring a slider to travel over both the zipper elements and the stringer tapes to open and close).
Although the Horita zipper may avoid a seepage problem through the stitches holding the zipper elements in place, this design is also deficient in a number of respects. First, the patent provides no teaching of how to attach the zipper to fabric or how to avoid seepage through seams which may be used to anchor the stringer tapes in place. This problem is probably exacerbated by the fact that the outer layer of the stringer tapes are not coated and should be susceptible to water wicking through them to mounting seams. Additionally, the abutment of the stringer tapes is again considered to be a restraint on free zipper movement.
In light of these difficulties, the most common method used today for protecting a zippered opening in a water resistant garment is to install a conventional zipper in conjunction with one or more storm flaps or other separate barrier layer. These flaps are attached to a garment so as to cover and/or back the zipper and prevent water from passing through. Outside storm flaps are normally held in place with a series of snaps or hook-and-loop fasteners. Barrier layers of this form have proven quite effective at eliminating water seepage while retaining a fully flexible and comfortable resealable closure.
Unfortunately, storm flaps are far from a panacea. These flaps tend to be quite expensive to manufacture and attach, requiring a significant amount of material and numerous additional mounting steps. Further, such barrier layers restrict ready user access to the zipper and, if not properly constructed, are prone to being caught in the zipper. Moreover, many designers have complained that the use of storm flaps in water-resistant garments is overly bulky, limits the range of design options, and leads to the garments looking far too similar to one another.
Accordingly, it is a primary purpose of the present invention to provide a water-resistant slide closure for a garment or other product and method for making the same which is effective at avoiding water seepage but is fully flexible and comfortable to wear or employ.
It is a further purpose of the present invention to provide such a water-resistant slide closure which does not rely on cumbersome additional barrier layers which add cost and complexity to the product while restricting free access to and movement of the zipper.
It is another purpose of the present invention to provide such a water-resistant slide closure which can be implemented with minimal cost and labor.
These and other purposes of the present invention will become evident from review of the following specification.